Abnormalities were found by immunofluorescence in five of 11 (45%) patients with transient acantholytic dermatosis. There was no consistent pattern to the abnormalities; for example, they were circulating antibodies to intercellular and basal cell antigens in a third. Deposits of Ig and/or C3 were present in lesions of three patients and C3 was present in the intercellular substance in the lesions of a fourth patient. These findings suggest that different immune mechanisms may be involved in the pathogenesis of transient acantholytic dermatosis.